How satnav maps are made
July 1, 2012 5:16 PM   Subscribe

"Flawed satnav instructions are the scapegoat for ridiculous round-trips, buses wedged under bridges, and ambulances taking life-threatening diversions. But few understand or appreciate how far mapping companies go to ensure the accuracy of the data they’re providing."
posted by vidur (27 comments total) 13 users marked this as a favorite
I'm less concerned about the road data being spot-on (although that is helpful), and more concerned with the times I've been sent up dirt roads and through "no trespassing, private property" signs because the satnav decided that was the way I should get to that place that I could have gotten to by staying on the main road for another mile and then making a turn.

Granted, I tend to use my satnav in small towns in rural WA/MT, so perhaps those places aren't driven by Nokia mapping cars all that often.
posted by hippybear at 6:07 PM on July 1, 2012 [2 favorites]

When a lorry driver wedged his 13-tonne truck between a house and an estate agent

Couldn't they have the estate agent take a few steps away from the truck?

Unless... is the estate agent a building? I'm pretty sure, though, that it's illegal for buildings to sell other buildings; it's like pimping or something. So it's probably not that.

Yeah, just have the (presumably human) estate agent step away. Problem solved.

And anyway, it's probably not the satnav that was to blame in that incident. I mean, hello, what is a lorry driver doing driving a truck?

Broken Britain!
posted by Sys Rq at 6:21 PM on July 1, 2012 [3 favorites]

So is "satnav" what they call GPS in the UK? I've never heard that term.
posted by octothorpe at 6:28 PM on July 1, 2012

the times I've been sent up dirt roads and through "no trespassing, private property" signs

I once had a job that involved driving every public right of way in a rural area. And yeah... half those signs are on public roads. People just post them, gate 'em off and over time convince themselves they own them.
posted by fshgrl at 6:29 PM on July 1, 2012 [7 favorites]

How hard is it to notice the "no trespassing" sign and then decide to not go down that road?

It's not difficult at all. I didn't take that road. But that doesn't mean the satnav didn't send me up that road. And it doesn't mean that I didn't have to back the delivery van I was driving 200 yards down a dirt road in the dark to where I could find a spot wide enough to execute a 25 point turn to get back out on the main road and then drive along until the satnav gave me the correct route about how to get there.
posted by hippybear at 6:31 PM on July 1, 2012 [2 favorites]

Yes it is octothorpe. "Sat"ellite "Nav"igation obviously.

GPS is a bit more specific as it refers to the US NAVSTAR system.

From wiki:

"As of October 2011, only the United States NAVSTAR Global Positioning System (GPS) and the Russian GLONASS are fully globally operational GNSSs. China is in the process of expanding its regional Beidou navigation system into the global Compass navigation system by 2020. The European Union's Galileo positioning system is a GNSS in initial deployment phase, scheduled to be fully operational by 2020 at the earliest. Several countries including France, Japan and India are in the process of developing regional navigation systems."
posted by panaceanot at 6:45 PM on July 1, 2012

Oh, man. Sat nav. So this last February my spouse and I were on a bus trip through the UK with a group of about 20 people. We had a coach driver from York who was FANTASTIC. . . . Until we got south of York. Then he was really dependent on the sat nav. One of the things I don't understand about sat nav is the talking to you thing. If you can't see the map, how on earth can you tell where you are going? Anyway, our driver was a helluva guy but the sat nav sent us into some seriously hellish situations, particularly in Bath, where road construction threw us way off the intended path, and if I'd opened a window, I probably could have touched the buildings.

However. The best part was trying to get to Stonehenge. We'd already been supplementing the sat nav with some iPhone aided navigation, but our iPhone navigator had had to stay back due to his partner's illness (they rented a car later that day to catch up to us), so one of our other, less . . . politic . . members was assisting with navigation. As he looked at the map on his phone and directed the driver to do precisely opposite what the sat nav was saying, the driver expressed a little trepidation at ignoring the sat nav. By this point we'd been trapped well and fully in the streets of Bath, along with various other "oh shit that's a cow path" sort of experiences, so our friend's response was all the funnier: "LOOK. You're going to have turn her off and just TRUST ME, okay?!"

No idea why a 60-some-year-old man would just trust a 30-something whippersnapper, but off went the sat nav, and we managed to use only normally sized roads to make our other destinations.

After the trip, our driver sent our trip leader a note: "I've put that sat nav in the bin."
posted by Medieval Maven at 7:13 PM on July 1, 2012

Remember driving on a new restricted access highway in Ireland. The GPS screamed and insisted we were driving over farm fields.
posted by Ironmouth at 7:29 PM on July 1, 2012

I would love a system with up to date construction information. Many is the time when I've been told to take a closed exit.
posted by desjardins at 8:02 PM on July 1, 2012

For some reason, Google really doesn't like the HOV restrictions on I-66 in Northern Virginia. Exactly how much Google happens to dislike these restrictions seems to vary day-by-day.

However, once you're on the road for a few miles, the paranoid ramblings of the Android satnav usually settle down, and either begrudgingly accepts that you're in the HOV lane, and provides you with sane directions, or tells you that you're trapped in an abyss from which there is no escape (a metaphor for Fairfax County if there ever was one).

However, one time, it gave me a fantastically terrible/awesome routing around a cloverleaf junction at West Falls Church. I wasn't that familiar with where I was going, so I followed the directions dutifully until I realized that HAL Google had completely lost it.

I was instructed to exit the highway onto the cloverleaf just past the Metro Station. Makes enough sense.

Okay, out of the cloverleaf...driving on the Google wants me to get back on the highway in the other direction. Weird, but makes enough sense...back in New Jersey, I remember a few roads where the exits didn't line up on both sides...

Back on the highway.... now Google wants me to exit immediately, back into the cloverleaf for a third time. I'm getting dizzy from driving in circles, but figure that this might make sense. There might have been a left-turn restriction on the overpass that Google couldn't figure out how to route me around. Google wants me to re-enter the cloverleaf, putting me back on the highway...right back where I started. What the deuce?

Turns out Google really didn't want me driving under the underpass while on the highway, and being a computer, sent me around all four leaves of the clover to prevent me from doing so. It then proceeded to attempt to send me along a similar routing around every single overpass on I-66. Somebody at Google had evidently marked the area underneath the bridges as unrouteable. I'm pretty sure that I'd have gotten caught in an infinite loop if that junction had been configured a bit differently....

With this in mind, I ignored the satnav's instructions until I ended up blowing past the exit that I was actually supposed to take.
posted by schmod at 8:16 PM on July 1, 2012 [6 favorites]

Then there was the time Michael and Dwight drove into a lake.

I mean seriously, who trusts those things?
posted by axiom at 8:24 PM on July 1, 2012

Obligatory. From The Office.
posted by twoleftfeet at 8:25 PM on July 1, 2012

Sorry, axiom. We both knew it was obligatory.
posted by twoleftfeet at 8:26 PM on July 1, 2012

Yeah, that time, twoleftfeet.
posted by axiom at 8:26 PM on July 1, 2012

You know, that really happened. Even after the warning message from The Office.
posted by twoleftfeet at 9:18 PM on July 1, 2012

Mapping and GPS discussions always conjure up nightmares from my days at Rand McNally and providing tech support for our street mapping software. The amount of rage seemed so disproportionate to the seemingly trivial matter of one's address not being listed. On the other hand though, I think there's a sense of identity or validation when you can pick out your address on a map. When we released city-to-city routing on the Palm a whole new level of rage/fascination was introduced. Just getting that to work in 2000 was a major accomplishment because we were doing it on hardware that just couldn't do what a Garmin would do. With our TDM products (for the trucking industry), there was a whole nother' level of detail that needed to be accounted for. Weight limits, bridge heights, haz-mat restrictions, just a nightmare amount of data to pack on top of what a regular Joe would need driving his Taurus to the Dells for a weekend. Seeing how quickly the mapping industry has grown and how far it has come continues to amaze me.
posted by KevinSkomsvold at 2:06 AM on July 2, 2012 [1 favorite]

Google street view in Scotland frequently ends up in strange places.
(forest plantation; jetty; farmyard; secure school; a boggy moor)
I bet it was fun reversing back up that jetty.

A couple of the more egregious ones have disappeared, including one of my favourites which was a 20 mile drive down a Forestry Commission track in Sutherland.

What is strange is that Google's definition of 'private road' seems rather inconsistent. Perhaps they had permission of the landowners to drive up these roads? That would explain how they got through the (nowadays padlocked) gate and up Glen Lednock, but not the ungated Glen Turret road a few miles away.

On the other hand, I suspect this is just inconsistency on the part of the Street View team. And if they're inconsistent about what's public and what's private, why would you expect the route planning features of Google Maps to be any better?
posted by Talkie Toaster at 3:46 AM on July 2, 2012

Interesting reading. I'm sorry to hear Tomtom is superior, as I don't much care for their hardware. But I'm not the average user, by any means. I've been using GPS, starting with a Garmin "I-Que" (Palm-based) about 10 years ago. I've used it in the UK, Europe, and South Africa.

I think this concept is as fabulous as anything. It's extremely nice to not be stressed about directions, ever. No paper maps to fumble with. And my poor eyesight isn't generally an issue. What I don't like, is mindlessly following a computer-generated route, however, I have to say, Tomtom is better than simply 'shortest' way.

See, 'shortest' is often worst! Garmin was lovely to route you straight through the heart of the biggest slum in South Africa, for example. A proper Tomtom wouldn't do that, as it knows to look for 'fastest' routes. But what I like for myself, is a good display and the ability to examine and alter the computer's plan. Maybe for scenery, maybe because you know something to avoid. Our fairly new Tomtom is horrible for this! It's a nightmare just trying to study the map!

For my tastes, I'd be far happier if I could twiddle with maps and route ideas, say on my ipad, while the actual routing device concerns with it's functions. If I come up with a better route, I could just tell the navigation, "This way, now!" and there I'd go. Mind, I am usually a passenger these days, doing the navigating. But even if I was driving, I'd stop to plan my route when I felt the desire.
posted by Goofyy at 5:04 AM on July 2, 2012

So is "satnav" what they call GPS in the UK? I've never heard that term.

GPS tells you where you are. Satnav navigates you to your destination. They are, in my mind at least, seperate things.
posted by EndsOfInvention at 5:35 AM on July 2, 2012

Talkie Toaster: Street View Partner Program
posted by helicomatic at 5:37 AM on July 2, 2012

Then again, the only way I'd ever drive in Malacca is with GPS turned on. That place is hell to navigate with regular maps and such; there are so many one-way alleys that I've always found it next to impossible to get a turning in time, for instance.

The best was when the old HP smartphone with GPS, whatsitsname, routed us through Singapore's Changi airport instead of around it; it calculated that the fastest way to go from the Pan-Island Expressway to the East Coast Parkway, was if we took the perimeter road inside Changi Airport. And we'd have, hadn't it been for a stern policeman; it was all dark, and crucially no closed gate, which meant that there was no warning at all when a Qantas flight emerged in front of us from nowhere and then simply took off.
posted by the cydonian at 5:46 AM on July 2, 2012 [1 favorite]

helicomatic: I'm aware of that, but the inconsistency of these decisions (and it's not like they've fully mapped out the Forestery Commission lands, for example) suggests that it's nothing to do with that.
posted by Talkie Toaster at 5:49 AM on July 2, 2012

Talkie Toaster: "Google street view in Scotland frequently ends up in strange places."

It also seems to happen in Mountaintop villages in Europe a lot. Mijas, Spain seems to take the cake for "I Have no idea how Google managed to wedge the Street View car into Europe or why..."
posted by schmod at 7:37 AM on July 2, 2012

I'm quite concerned about the new apple maps under ios6. I'm using beta 2 and the visuals and quality of info available are still woefully below what was present in the google version of the maps app under ios5.
posted by modernnomad at 10:37 AM on July 2, 2012

I mean seriously, who trusts those things?

People like me, driving a 700 mile delivery route overnight through rural ID and MT to places I've seen once from the passenger seat during training but have never driven to, and it's 2am and while the name of the place is familiar, I sure as hell can't conjure up an image of what the building looks like, let alone how to get there off the main highway.
posted by hippybear at 6:35 PM on July 2, 2012

"I Have no idea how Google managed to wedge the Street View car into Europe or why..."

They have (what I call as) a Google Rickshaw for narrow roads. They famously used it here in Singapore to take pictures of pedestrian-only promenades.
posted by the cydonian at 8:45 PM on July 2, 2012

ahhh... I love my satnav... mostly.

I've done three long European motorbike trips, two with paper maps and one with a satnav. The first two consisted of me constantly taking my eyes off the road to look at maps stuck to the tank, invariably taking a couple of seconds to figure out where we *are* first, taking lots of wrong turnings, and managing to go through the centres of Paris and Luxembourg City during rush hour instead of bypassing them. And never having maps of quite the proper scale either. (Plus the added stress of making sure the other bikes were still behind me!)

With the satnav - no problem. I can't remember it telling me to go the wrong way very often at all...
posted by alan2001 at 4:43 AM on July 3, 2012

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